I just went from a 24 tooth rear sprocket to a 20 tooth sprocket on my Terra Trike. How many chain links am I going to have to remove, since the chain is now very loose.
Thanks.

did your small/small combo change? 34x11 if compact, maybe 39x12 max on a standard crankset.

if not.. that chain is fine. I run the longest chain possible and as a result I can switch from 11-23 cassette to 11-32 without changing my chain.

Something doesn't make sense here. The RD should have picked up the slack unless your chain was already way too long. Think of it this way -- the RD has to be able to deal with your smallest cog, so reducing the size of your largest ones should have no effect on performance.

I'm a firm believer in not counting links for purposes of sizing -- just size as if you were putting on the chain for the first time. ColinL: this guy's riding a trike with a triple up front and I'm not sure what the back.

Ramwing, the best way to size your chain is probably to put the gears in the big ring biggest cog combo with the chain skipping the RD and then adding one more full link.

1. I agree and that's why I asked what I did. increasing your largest cog or increasing your chainring size(s) can result in a chain too short, but it's a lot harder to have a chain which was working suddenly be too long.

2. I knew it wasn't a road bike but I didn't know what it had drivetrain-wise. I assumed it has a rear derailleur.

3. that is one way to do it, a way that can result in a chain being too short if you to a cassette with a larger cog than what you sized it with. you can also run the longest chain possible, which involves putting your chain in the small/small combo and measuring conservatively, then removing a link until the drivetrain functions. I know we don't ride in small/small because of epic crosschaining, that's not the point. the point is that you can use any cassette your RD supports without resizing the chain.


perhaps the OP has threaded the chain the wrong way through the rear derailleur.

That idea occurred to me, but I don't like it because he shouldn't have messed with his chain at all when swapping out the cassette. But then again, there are not that many things that could have even been touched.

Welp, I popped out a link and everything is perfect. That Alfine is in a different world than the old Sturmey. Smmoth and silent. With the sprocket combination I can now use all 8 speeds instead of the middle 5, or so on the old hub. So, now I'm into the longevity testing phase. So, thanks to everyone for the advice. I appreciate it.

Ah. You needed to note that you were using an Internal Gear Hub, not a cassette.